content: /*
   * Copyright 2011-2016 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package ix;
  
  import java.util.Iterator;
  
  final class IxGenerate<T, S> extends Ix<T> {
  
      final IxSupplier<S> stateFactory;
  
      final IxFunction2<S, IxEmitter<T>, S> generator;
  
      final IxConsumer<? super S> stateDisposer;
  
      IxGenerate(IxSupplier<S> stateFactory, IxFunction2<S, IxEmitter<T>, S> generator, IxConsumer<? super S> stateDisposer) {
          this.stateFactory = stateFactory;
          this.generator = generator;
          this.stateDisposer = stateDisposer;
      }
  
      @Override
      public Iterator<T> iterator() {
          return new GenerateIterator<T, S>(stateFactory.get(), generator, stateDisposer);
      }
  
      static final class GenerateIterator<T, S> extends IxBaseIterator<T>
      implements IxEmitter<T> {
  
          final IxFunction2<S, IxEmitter<T>, S> generator;
  
          final IxConsumer<? super S> stateDisposer;
  
          S state;
  
          GenerateIterator(S state, IxFunction2<S, IxEmitter<T>, S> generator, IxConsumer<? super S> stateDisposer) {
              this.state = state;
              this.generator = generator;
              this.stateDisposer = stateDisposer;
          }
  
          @Override
          protected boolean moveNext() {
  
              state = generator.apply(state, this);
  
              boolean hv = hasValue;
              boolean d = done;
              if (!hv && !d) {
                  stateDisposer.accept(state);
                  throw new IllegalStateException("The generator didn't call any of the onXXX methods!");
              }
              if (d) {
                  stateDisposer.accept(state);
              }
              return hv;
          }
  
          @Override
          public void onNext(T t) {
              value = t;
              hasValue = true;
          }
  
          @Override
          public void onComplete() {
              done = true;
          }
      }
  }
  